Electrical system



May 22, 1928.

S. P. LEVENBERG ELECTRICAL SYSTEM Filed Dec. 8, 1923 2 Sheets-Sheet 1all" ATTORNEY May 22, 1928.

S. P. LEVENBERG ELECTRICAL SYSTEI Filed D60. 1923 2 Sheets-Sheet 2lNvENl 'p 7 2 p BY ATTORNEY Patented May 22, 1928- .um'rso STATES PATENTOFFICE.

SAMUEL P. LEVENBERG, 01' NEW YORK. N. Y., ABBIGNOB TO rm: nvmm con-POBATION, 0]? NEW YORK, N. Y.,

A CORPORATION 0] m YORK.

ELECTRICAL SYSTEM.

Application men December s,'1a2a. Serial m. mass.

This invention relates to electrical circuits and with regard to itsmore specific features to a circuit for the reception of electricalwaves of radio frequency.

An object of this invention is to provide a system of the characterdescribed in WhlCh the power supplied for the system may taken fromstandard power mains in a sultable and satisfactory manner.

A further object is to provide a system of the character described whichwill operate without distortion or extraneous noises, and which willproduce a clear tone of maximum volume. A further object is to provide adevice of the character described which will operate efficiently andsatisfactorily with a minimum of power and which shall be simple andeflicient.

Other objects will be in part obvious and will in part appearhereinafter.

The invention accordingly comprises the features of construction,combinations of elements, and arrangement of parts, which will beexemplified in the construction hereinafter set forth and the scope ofthe application of which will be indicated in the claims.

In modern radio work it is customary to utilize vacuum tubes for thecreation and amplification and rectification or detection of radiooscillations, and such tubes utilize sources of unidirectional energy.As it is this energy which is directly converted into sound waves, it isimportant that it be free from oscillations which may distort thereception. It is usual at the present time, therefore, to employ primaryor secondary batteries to furnish this energy.

In accordance with this invention it is possible so to eliminate highfrequenc oscil lations that the energy required or the system may betaken directly from power means.

For a fuller understanding of the nature and objects of the inventionreference should be had to the following detailed description taken inconnection with the accompanying drawings, in which:

Figure 1 is a wiring diagram of a system embodying this invention havingthree tubes arranged to act respectively as detector and twg stages ofaudio. frequency amplification; an

Fig. 2 is a diagram of a system embodying two stages of radio frequencyamplifica- The numeral 1 indicates an aerial connected to the ground asat 2 through a reactance 3 which may be variable as shown at 4 forpurposes of tuning. A second reactance 5 coupled to the reactance 3furnishes a source 0 high frequency oscillations for the system as willbe later described. The numerals 6, 7 and 8 represent respectively adetectin tube and first and second stage audio amp ifying tubes. Thecoil 5 is connected at one side to the grid 9 of the tube 6 through acondenser 10 and grid leak 11 and at the other side to the filamentcircuit. If desired this latter connection ma be made through acondenser 12 and big resistance 13. A variable condenser 14 may beplaced in shunt with the coil 5 for the purpose of tuning it.

JThe radio system here employed may be operated from power lines usingeither direct current or alternating current. In the latter case thecurrent is first rectified and converted into a. non-pulsating directcurrent, and thereafter utilized in the system. If direct current is tobe employed it may be connected directly to the system without utilizingthe rectifying apparatus. For this reason the alternating current systemwill be first described, thereafter the direct current connection may bereadily understood.

The numeral 15 represents generically an alternating current generator,the ener from which is carried to the primary 16 of a transformer 17having a secondary 18 of a voltage suflicient to serve the plate circuitof the various vacuum tubes and a. power capacity suflicient to serveboth plate and filament circuits. As it is ordinarily desirable toutilize both valves of the wave in order to simplify the rectificationand the elimination of the oscillations, this secondary 18 is referablysplit at its center point by provi atap 19. Bytheuseofn.

rectifier in each of the extremes 20 and 21 of the winding l8 :1.pulsatingimidirectional current may be caused to return through the tap19.

A convenient and ellicient form of rectifier comprises a vacuum tube 22having'the filament 23 and two anodes 24 and 2;) connected respectivelyto the terminals 20 and 2t of the winding, 18. The lilamcnt 2?; of thistube is itself fed with energy from a secondary 26 upon the transformer17 which is also split to provide a central tap 2T connected to a wire23 which furnishes acommon return for both halves of the wave. There isthus set up upon the wire 29 connected to the tap it) and the wire 28 aunidirectional pulsatin; current.

In order to obliterate fluctuations in the How there is connected inseries with one of these wires, as for example the wire 28, aninductance 30 furnishing a path of low resistance tor the direct currentbut resisting the passage thcrethrough of the fluctuations. A condenserill may be bridged between the near and 32 of this inductance and theopposite terminal 29 to furnish a short circuit path of low resistancefor the fluctuations and another condenser 33 may connect the other side3t of this inductance with the pole 29 servinp to short circuit againsuch fluctuations .s pass through the inductance coil. By thisarrangement the portions oi? the fluctuations are immediately shortcircuited by the condenser 31 While the inductance 30 and the condenser33 in so far as the fluctuating; portion of the current is concerned arein series with each other in shunt across it. In this manner a measureof series resonance exists between the condenser 33 and the inductance30, building up a high counter electromotire force in the coil 80 toresist the passage of the fluctuation of the current.

The reactance coil 30 is of comparatively high reactance, and in someinstances it has been found desirable that the coil have a reactance ofapproximately 14 henrics while condensers 3t and 33 are of such value asto furnish substantially a short circuit for the high frequencyoscillations, condensers ha"- ing a capacity of approximately 11)microfarads having been found suitable. With this arrangement there isprovided between the terminals 28 and 34 a direct current c0m parativelyfree from distortions.

A second reactance having an inductance of substantially the samemagnitude as the coil 30 is placed in series between the terminal 34 andthe radio circuits to hold back from the radio apparatus the highfrequency oscillations in the circuit and the opposite terminal 36 ofthis reactance furnishes the source of direct current positive energyfor the system. A switch 37 may be interposed between the terminal ?Aand the inductance 35 and a similar switch 38 may be interposed betweenthe terminal 29 and a terminal 39 constituting the negative terminal ofthe system.

The filaments 40, 41 and 42 of the tubes 6, T and 8 respectively. areconnected in series and one side of the tube 8 is connected through alead 42% with the negative. terminal I39 while the opposite terminal ofthe filament ll) is connected by lead -14 with one side 45 of a highresistance -16 connected at its other side with the positive terminal36. This resistance 46 is preferably adjustable as shown at 47 to permitthe adjustment of the current flowing through the filaments.

Under many circumstances the filaments ol' the various tubes willpossess sutliciently identical characteristics so that no separatecontrol of the current through them will be required, but such separatecontrol under other circumstances being desirable, may be atlorded byvariable resistances -18, 49 and ml in shunt with the filaments. Thesevariable resistances preferably comprise a fixed resistance in permanentshunt across the filament. a portion of which may be short cir cuited asdesired. i

Electrical energy for the plate 51 of the tube 6 is derived from aterminal 52 connected through a high resistance with the positiveterminal 36, and inserted in series in this circuit is the primary 54 ofan audio transformer, A, the secondary 55 of which connects the grid 56of the tube 7 with the wire -13. The plate 57 of the tube 7 receives itsenergy from a tap 58 upon the resistance 53 to leave a portion 59 ofthat resistance in the said plate circuit. This plate circuit has inseries with it the primary 60 of a second audio transformer B, thesecondary 61 of which connects the grid 62 of the tube 9 with the wire43.

Three pairs of terminals, 63 and 64, 65 and 66, and 67 and 68. may beprovided at any suitable location for connection to the translatingdevice, such as for example as a. telephone or loud speaker, the firstpair permitting connection of the translating device direct to the firsttube, the second pair furnishing one stage of amplification and thethird utilizing both stages of amplification. To this end the terminals63, 66 and 68 may be connected respectively to the plates of the first,second and third tubes, while the remaining terminals 64, 65 and 67 areconnected direct to the terminal 52. An adjustable resistance 69 may beprovided in the plate circuit of the last tube to control the volume ofsound.

Three condensers 7 O, 71 and 72 are connected in delta formation, one ofthe terminals of the delta being connected to the negative terminal 39,one to the filament terminal 45 and one to the positive plate terminal52.

For the purpose of eliminating the high frequency oscillations from thegenerator of the system it is desirable that one side of the A. C.current shall be grounded as shown at 73, and one of the terminals 28 or29 is preferably connected to this grounded side through a condenser 74.lVith the apparatus as described the terminal 39 will represent thenegative potential of the system.

The resistance 46 will be sutlicient to limit the filament currenteither with or without the use of the shunt resistance as 48, 49 and 50to the desired value. Thus the terminal 45 will be at a higher positivepotential than the negative return 39. The resistances 53 and 59 will beof such a value, when in series with the plate circuit as described, asto limit the plate current to a predetermined value, and with such anarran ement. particularly if the initial D. C. re tage be materiallyhigher than that required across the plate the resistances 53 and 59will have the effect of causing a comparatively constant plate circuitto flow in the tubes and this plate circuit operating through thevariable resistances from plate to filament of the tube will cause a.varying potential from plate to filament.

The condensers at 71 and 72 may suitably be of the order of one-halfmicrofarads each, Whereas the condenser may suitably be approximatelytwo microfarads.

If it is desirable to utilize the system without the amplifying tubesthe translating device may be placed directly across between theterminals 63 and 64, in which case it is in parallel with the primary 54of the transformer A or if one stage of amplification is desired it maybe placed between the terminals 65 and 66 in which case it is connectedbetween the plate 57 and the terminal 52.

In the system illustrated in Fig. 2, two additional tubes are providedfor radio frequency amplification. The tube has its grid 81 connecteddirectly to the tuning inductance 205 which is coupled to the aerialinductance 203 and has its plate circuit 82 connected to the primary 83of a radio frequency transformer C receiving its energy from theterminal 52. The secondary 84 of this radio transformer is directlyconnected to the grid 85 of the second tube 86 and may be arranged to betuned as by a variable condenser in multiple with it as shown at 87. Theplate 88 of the tube 86 is connected through the primary 89 of the radiotransformer D to the terminal 52 and the secondary 90 of thistransformer D is connected with the grid 209 of a detector tube 206through the medium of a. grid condenser 210 and a grid leak 211. Thesecondary of this transformer D is also provided with a variablecondenser 91 for tuningpurposw.

The connections tothe plate circuits of the audio frequency tubes 207and 208 are simiwith the same voltage as the plate circuits to theamplifying tubes, if desired, by he.

ing connected directly to the terminal 59.

lVith this modification, filaments of all of the tubes may be connectedin series but it is desirable that the filaments he placed in such anorder and that the grid circuit returns from the various tubes be madeto points of such potential as to induce upon the grid of each tube theparticular bias most desirable for its operation. a

A convenient and efiective way of producing a practical result is thatillustrated in which the filament 93 of the tube 86 and the filament 92of the tube 80 may be inserted in series between the filament of thedetector tube 206 and the filaments 241 and 242 of the tubes 207 and 208respectively. In this manner the current traverses first the filament240 of the detector tube and then the filaments 93, 92, 241 and 242 inorder.

The grid return from the two radio frequency tubes and from the detectortube may then be made to the wire 94 connectlng the filament 92 with thefilament 241. Thus, as illustrated, each of these grids has a nega' tirebias relative to the other filaments, which bias is greatest-upon thedetector tube and least upon the tube 80. The grid return from the tubes207 and 208 may be made directly to the negative side of the system asin the previous modification. With the circuit as shown in Fig- 1 theprimary inductance 3 may be tuned in any suitable manner, and thesecondary inductance 5 may be tuned by the condenser 14. The oscillatorypotential set up in the coil 5 1s impremed upon the grid 9 and thefilament 40 through the condensers 10 and 12, and causes correspondingfluctuations in the effective resistance between the plate 51 and thefilament. The primary 54 has a direct current flowing through it fromthe terminal 36 through the resistance 53 and the terminal 52, but byreason of the fact that the terminal 53 is short circuited to thefilament through the condensers 71 and 72 fluctuations in the potentialacross from the plate to the filament may cause a direct oscillatorycurrent between the plate. the primary. the condensers, and back to thefilament. Thus a separate pathway is provided for the alternatingcurrent circuit and for the direct current circuit through the plate.

The operation of the system 12 of Fig. 2 is similar to the operation ofthe system in Fig. 1. The particular point at which each individual gridreturn should be made is dependent upon the particular characteristicsof the tube employed but a very great variety is possible due to thefact that any grid return may be connected to any point of the series offilament circuit which produces the proper bias.

Since certain changes may be made in the above construction andditi'erent embodiments of the invention could he made without departingfrom the scope thereof, it is intended that all matter contained in theabove description or shown in the accompanying drawing shall beinterpreted as illustrative and not in a limiting sense.

It is also to be understood that the following claims are intended tocover all of the generic and specific features of the invention hereindescribed. and all statements of the scope of the invention which, as amatter of language, might be said to fall therebetween.

Having described my invention, what I claim as new and desire to secureby Letters Patent, is:

1. A radio system adapted for use from power mains comprising incombination a plate circuit. a iilament circuit and means for bv-passing audio frequency oscillations between the terminals of thefilament circuit comprising a large capacity condenser connected acrossthe filament terminals.

2. In a device for the elimination of extraneous noises from a radio setoperated from a power main, in combination, three large capacitycondensers connected in delta and having terminals adapted to beconnected respectively to the terminals of the filament circuit and tothe plate circuit of the set respectively.

ii. in a device for the elimination of extraneous noises from a radioset operated from a power main, in combination, three large capacitycondensers connected in delta and having terminals, two of which areadapted to be connected to the terminals of the filament circuit of theset and an impedance having one end connected to the third of saidterminals and having at the other end of the impedance a terminaladapted to be connected to the power circuit.

4. ln a device for the elimination of extraneous noises from a radio setoperated from a. power main. in combination, three large capacitycondensers connected in delta. and having terminals, two of which areadapted to be connected to the terminals of the filament circuit of theset and a resistance connected at one end to the third of said terminalsand having at the other end of the resistance a terminal adapted to beconnected to the power circuit.

5. ln a'device for the elimination of extraneous noises from a radio setoperated from a. power main, in combination, three large capacitycondensers connected in delta and having terminals, two of which areadapted to be connected to the terminals of the tilament circuit of theset and a resistance connected at one end to the third of said terminalsand having at its other end a terminal and a choke reactance connectedto the said terminal of said resistance.

(3. In a device for the elimination of extraneous noises from aradio setoperated from a power main, in combination, two large apacity condensersconnected in series, and two resistances connected together in seriesand having an inside and two outside terminals, one of the outsideterminals adapted to be connected to the plate circuit of a radio setand being connected to one of the condenser terminals, and the otheroutside terminal being connected to another of the condenser terminals,the third condenser terminal being adapted to be. connected to thenegative side of the power main, the intermediate resistance terminalbeing adapted to be connected to the power side of the positive main.

7. In a device for the elimination ot extraneous noises from a radio setoperated from a power main, in combination, two large capacitycondensers connected in series, and two resistances connected togetherin series and having an inside and two out side terminals, one of theoutside terminals adapted to be connected to the plate circuit of aradio set and being, connected to one oi" the condenser terminals, andthe other outside terminal being connected to another of the condenserterminals, the third condenser terminal being adapted to be connected tothe negative side of the power main, and a choke coil connected to saidintermediate resistance terminal and adapted to he connected to thepositive side of the power main.

8. A radio set adapted for operation direct from uni-directional powermains without extraneous noises, comprising, in combination, a pluralityof radio tubes having their filaments in series and plate circuitsincluding translating devices, a large capacity condenser connectedacross said series of lilaments and a large capacity condenserconnecting each terminal of said series of lilaments with the platecircuits beyond the translating devices.

9. A radio set adapted for operation direct from uni-directional powermains without extraneous noises, comprising, in combination, a pluralityof radio tubes having their filaments in series and plate circuitsincluding translating devices and a large capacity condenser connectedacross said series of lilaments and a large capacity condenserconnecting each terminal of said series of lilaments with the platecircuits beyond the translating devices and a resistance having one sideconnected to the positive side of the filament circuit and adapted to beconnected by its other side to the positive side of the power main.

10. A device of the character described accuses for operating a radiocircuit from a uni-di rectional source of power comprisin an electrontube having a two terminal cat iode and a plate circuit, an impedanceconnected at one end to said plate circuit and having a terminal adaptedfor connection to the positive side of source of power and means forlay-passing audio frequency currents between the terminals of thecathode comprisinglarge capacity condensers connecting the said end ofsaid impedance with each of the cathode terminals.

11. A device of the character described for operating a radio circuitfrom a uni-directional source of power comprising an elec tron tubehaving a two terminal cathode and a plate circuit, an impedance havingone end connected to said plate circuit and having a terminal adaptedfor connection to the positive side of source of power and a. largecapacity condenser connecting the said end of said impedance with acathode terminal and a large capacity condenser connecting terminals ofsaid cathode.

12. A device of the character described for operating a radio circuitfrom a uni-directlonal source of power comprising an electron tubehaving a two terminal cathode and a plate circuit, an impedance havingone end,

connected to said plate circuit and having a terminal adapted forconnection to the positive side of source of power and a large capacitycondenser connecting the said end of said impedance with both terminalsof said cathode and a large capacity condenser connecting terminals ofsaid cathode.

13. A device of the character described for operating a radio circuitfrom a uni-directional source of wer comprising a plurality of electrontubes having their cathodes connected in a series each of said tubeshaving a plate, a translating device for each of said tubes having oneterminal connected to said plate and an outer terminal, a. condenserconnecting each of said outer terminals with both terminals of saidcathode and a large capacity condenser directly connecting the terminalsof the cathode circuit.

14. A device of the character described for operating a radio circuitfrom a uni-directional source of power comprising an electron tubehaving a cathode and a plate circuit, a plate circuit resistanceconnected at one end to said plate circuit and a cathode resistanceconnected at one end to said cathode both of said resistances havingtheir other terminals connected together, and two large capacitycondensers one for connecting the said end of said plate circuitresistanc with each cathode terminal. a

15. A device of the character described for operating a radio circuitfrom a uni-directional source of power comprising an electron tubehaving a cathode and a. plate circuit,' a plate circuit resistanceconnected at one end to said plate circuit and a cathode resistanceconnected at one end to said cathode both of said resistances havingtheir other terminals connected together, and two large capacitycondensers one for connecting the said end of said plate circuitresistance with each cathode terminal and a lar e capacity condenser forconnecting the catlode terminals.

16. A device of the character described for operating a radio circuitfrom a uni-directional source of power comprising an electron tubehaving a cathode and a plate circuit, a plate circuit resistanceconnected at one end to said plate-circuit and a cathode resistanceconnected at one end to said cathode both of said resistances havingtheir other terminals connected together, and two large capacitycondensers one for connecting the said end to said plate circuitresistance with each cathode terminal and a choke coil for connectingsaid terminals to the positive side of the power supply.

17. A device of the character described including in combination aplurality of electron tubes in cascade amplification, means for feedingthe plate circuits of said tubes with energy from a generator source ofpower, said source including means for maintaining a substantiallconstant unidirectional electrical supp y, a resistance havin oneterminal connected to the positive side of the source of power andhaving another terminal connected to the plate circuits of said tubes,said resistance being of such ma nitude as to create a substantialvoltage rop across itsterminals while in use whereby the plate circuitsof said tubes may be supplied with a current of a materially lowervoltage than said source of power and means for substantially shortcircuiting all audio-frequency currents from the source of powercomprislng a condenser of not less than one half micro-fared connectingsaid other terminal of said resistance with the cathodes'of the tubes.

18. A device of the character described including in combination aplurality of electron tubes in cascade amplification, means for feedingthe plate circuit of said tubes with energy from a generator source ofpower, said source including means for maintaining a substantiallyconstant uni-directional electrical supply, a resistance having oneterminal connected to the positive side of the source of power andhaving another terminal connected to the plate circuits of the tubes ofthe earlier stages of amplification, said resistance bein of suchmagnitude as to create a substantial voltage drop across its terminalswhile in use whereby the plate circuits of said earlier tubes may besupplied with a current of a materially lower voltage than said sourceof power and means for substantially short circuiting allaudio-frequency currents from the source out extraneous noisescomprising in combio l' power comprising a condenser of not less nationa plurality of electron tubes having than one half micro-faredconnecting said their filaments in series and plate circuits otherterminal of said resistance with the including translating devices andmeans cathodes of the tubes, and a tap on said rccomprising largecapacity condensers for 5 sistancc for i'nrnishin; a higher voltagecursubstantially short circuiting all audio-frerent to the tubes of thelater stages of amquency oscillations between the terminals ofplitication. the filament circuit and the plate circuit.

19. A radio set adapted for operation diin testimony whereof I nfi'ix mysignature. 1U rect from uui-dircctional power mains witl1- SAMUEL P.LEVENBERG.

CERTIFICATE OF CORRECTION.

Patent No. 1,670,893. Granted May 22, 1928 to SAMUEL P. LEVENBERG.

it is hereby certified that the name of the assignee in the abovenumbered patent was erroneously written and printed as "The LevenbnrgCorporation" Whereas said name should have been written and printed as"The Lavenburg Corporation"; page 1, line 106. for the word "valves"read "halves; page 4, line 8 5. claim 6, for the word "power" read"positive", and line 86, for the word "positive" read "power"; and thatthe said Letters Patent should be read with these corrections thereinthat the same may conform to the record of the case in the PatentOffice.

Signed and sealed this 29th day of January, A. D. 1929.

M. J. Moore, (Seal) Acting Commissioner of Patents.

DISCLAIM ER 1,670,893.-Samuel P. Le zrenberg, New York, N. Y. ELECTRICALSYs'rnM. Patent dated May 22, 1928. Disclaimer filed May 18, 1931, bythe nssignee, Radio Corporation of America. i

Hereby enters this disclaimer to c aim 1 in the said specification whichis in the following words, to wit:

A radio system adapted for use from power mains com rising incombination a. plate circuit, a filament circuit and means forby-pessing nu io frequency oscillations between the terminals of thefilament circuit comprising a large capacity condenser connected acrossthe filament terminals.

[Qfiicial Gazette June .9, 1931.]-

all audio-frequency currents from the source out extraneous noisescomprising in combio l' power comprising a condenser of not less nationa plurality of electron tubes having than one half micro-faredconnecting said their filaments in series and plate circuits otherterminal of said resistance with the including translating devices andmeans cathodes of the tubes, and a tap on said rccomprising largecapacity condensers for 5 sistancc for i'nrnishin; a higher voltagecursubstantially short circuiting all audio-frerent to the tubes of thelater stages of amquency oscillations between the terminals ofplitication. the filament circuit and the plate circuit.

19. A radio set adapted for operation diin testimony whereof I nfi'ix mysignature. 1U rect from uui-dircctional power mains witl1- SAMUEL P.LEVENBERG.

CERTIFICATE OF CORRECTION.

Patent No. 1,670,893. Granted May 22, 1928 to SAMUEL P. LEVENBERG.

it is hereby certified that the name of the assignee in the abovenumbered patent was erroneously written and printed as "The LevenbnrgCorporation" Whereas said name should have been written and printed as"The Lavenburg Corporation"; page 1, line 106. for the word "valves"read "halves; page 4, line 8 5. claim 6, for the word "power" read"positive", and line 86, for the word "positive" read "power"; and thatthe said Letters Patent should be read with these corrections thereinthat the same may conform to the record of the case in the PatentOffice.

Signed and sealed this 29th day of January, A. D. 1929.

M. J. Moore, (Seal) Acting Commissioner of Patents.

DISCLAIM ER 1,670,893.-Samuel P. Le zrenberg, New York, N. Y. ELECTRICALSYs'rnM. Patent dated May 22, 1928. Disclaimer filed May 18, 1931, bythe nssignee, Radio Corporation of America. i

Hereby enters this disclaimer to c aim 1 in the said specification whichis in the following words, to wit:

A radio system adapted for use from power mains com rising incombination a. plate circuit, a filament circuit and means forby-pessing nu io frequency oscillations between the terminals of thefilament circuit comprising a large capacity condenser connected acrossthe filament terminals.

[Qfiicial Gazette June .9, 1931.]-

